Werner complexes of 4-acetyl-pyridine



United States Patent 01 WERNER COMPLEXES OF 4-iACETYL-PYRIDINE William D. Schaefier, Pomona, and William Smith Dorsey, Fullerton, Calif, assignors to Union Oil Company of California, LosAngeles, Calif., a corporation of California No Drawing. Application April 29, 1957 Serial No. 655,541

5 Claims. (Cl. 260?270) This invention relates to certain new Werner comp xes which ar i f nd o. xhibit the. unusu l proper y, q e nso a as e wa eetseleetivdy absorbi g. or clathrating, ethylbenzene into their rystal tr ture in. strong preference, to, hectherxylene. isom r Th y may hen e b temnlore tor eparatingethylbenaene from mixtures containing any one or more of the other COCH; COCH;

wherein M is a metal of atomic number to 28 (i.e. manganese, iron, cobalt or nickel).

When any of the above complexes are triturated with, or precipitated in the presence of, a liquid mixture of isomeric xylenes, it is found that the ethylbenzene is selectively integrated into the crystal structure, forming what is presently regarded as a clathrate. The other isomers, i.e. p-xylene, m-xylene and o-xylene, are strongly rejected from the clathrate. The solid clathrate may then be separated from the liquid phase, and decomposed with acid or heat to recover the ethylbenzene concentrate.

The corresponding Werner complexes of other nitrogen bases, e.g. 3-cyano pyridine, nicotinamide, isonicotinamide, ethyl isoniconate, 4-methyl pyridine, and 4- ethylpyridine, do not clathrate ethylbenzene in preference to p-xylene, the p-xylene being selectively clathrated in preference to all the other isomers. However, some ethylbenzene is also clathrated, and several clathration stages are necessary to obtain complete separation of pxylene from ethylbenzene. By using the 4-acetyl-pyridine complexes of this invention to remove ethylbenzene from the feed to, or an extract from, a p-xylene clathration process, the number of stages necessary to obtain complete resolution of p-xylene and ethylbenzene is considerably reduced.

The new complexes may be easily prepared by simply admixing the proper mole-ratios of metal thiocyanate (one mole), and the pyridine base (four moles or more), normally at room temperatures, although higher or lower temperatures may be employed. If desired the metal thiocyanate may be first dissolved in a solvent such as water 2,905,084 Patented Sept. 22, 1959 containing excess thiocyan-ate ions, e.g. KSCN, and the complex precipitated by addition ofthe 4-acetyl-pyridine. The complexesare substantiallyinsoluble in water, and soluble.irrch-loroform and methyl cellosolve.

when working in aqueous solutions, it is not necessary to start: with pure metal thiocyanates. Any soluble salt which forms a more soluble complex with the 4-acetylpyridine than does. the thiocyanat-e may. beinitially dissolved in the solvent; thiocyanate ions are then added, nd. fi ly h .ety ry idi .v wh reupon. th s soluble thi'ocyanate complex is selectiyelyprecipitated in c or a it e awf: m ss. action- T e ompl xe f the t a s. a more solubl in Water n e o r po ing thic yana and hence it is convenient to use solutions of meta], chlorides or brom de a a i g. ma ria s, first add n th r an excess. of alk li'me l h qcya at cg.- NaSC KSCN, NH 'SCN', etc., then adding the 4-acetyl-pyridine. The r lting pr c p s h n recover y. filtration, washed i r. or other ppropriat olvent, a d. dried. at mpe t e 2 .0 Highe emp rare a e ik ly toc us e omposition.

A suitable meth d o Prepa ati n. s illustrated. in h following example:

About6" grams (0:05 mole)- of 4-acetyl-pyridine was dissolved in 5 m1. of water. Another solution was prepared containing 2.98 grams (0.0125 mole) of nickel chloride (NiCl .6H O) and 2.05 grams (0.025 mole) of sodium thiocyanate dissolved in 15 ml. of water. The two solutions were then mixed and stirred, whereupon a blue precipitate formed. The precipitate was filtered off, washed several times with water, and air dried overnight.

A pale blue solid was obtained in 91% yield, melting at 289 C. Elemental analysis was as follows:

0 H 5 Ni Calculated 54.6 4.3 9.72 8.9 Found 56.1 4.45 9.9 8.05

The product was hence nickel tetra (4-acetyl-pyridine) dithiocyanate.

By substituting mole-equivalent proportions of manmangese, iron or cobalt chlorides for nickel chloride in the above example, the corresponding Werner complexes of those metals are obtained in similar yields and purities. The resulting complexes are:

Physical Complex appearance (1) Mantganous tetra-(4-acetyl-pyridine) dithiocya- White solid.

no. e. (2) Ferrous tetraFM-acetyl-pyridine) dithioeyanate Tan solid. (3) Cobalt tetra-(4-acetyl-pyridine) dithiocyanate-.-- Pink solid.

All of the above complexes exhibit selective clathrating properties for ethylbenzene, similar to that shown in the following example:

EXAMPLE. II

r 3 then washed three times Na SO Ultra violet spectranalysis of the hydrocarbon phase, and of the original xylene mixture, showed that the isomer distribution was as follows:

Table 1 Volume Percent Ethylp-Xylene rn-Xylene o-Xylene benzene reed -Q. 19. 9 45. 5 19. a 15.3 Hydrocarbon from clathrate. 11. 5 23. 5 10. 4 54. 6

with water and dried' over- 43 Other 'specific'complexes, methods of preparation and uses will readily occur to those skilled in the art. The

true scope of the invention is intended to be embraced by the following claims:

We claim: 1. A Werner complex having the formula:

coon, -coon,

GOGH; OCH;

0 wherein M is metal of atomic number 25 to 28 inclusive.

paints and the like. Their solubility in many organic 501- I vents, e.g. aromatic hydrocarbons, renders them useful as impregn'ants for intimately depositing catalytic metals on hydrophobic surfaces as e.g. activated carbon and the like. Other uses will be apparent to those skilled in the art.

This application is a continuation-in-part of our prior application Serial No. 466,939, filed November 4, 1954.

2. Nickel tetra(4-acetyl-pyridine) dithiocyanate.

3. Cobalt tetra (4-acetyl-pyridine) dithiocyanate.

- 4; Manganese tetra(4-acetyl-pyridine) dithiocyanate.

5. Ferrous Jtetra(4-acety1-pyridi ne) dithiocyanate.

References Cited in the file of this patent UNITED STATES PATENTS .2,774,802' Christian Dec. 18, 1956 Schaefer July 9, 1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,905,684 September 22, 1959 William D. Schaeffer et al It is hereby certified that error appears in the -printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, lines 45 and 46, for "man-mangese!v read manganese column 4, line 14, claim 1, in the chemical formula, centermost symbol,

for "N" read M Signed and sealed this 15th day of March 1960.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents Attesting Officer 

1. A WERNER COMPLEX HAVING THE FORMULA: 